US5209967A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure sensitive membrane and method therefor
Assignee: 3M Co
•
Filing: 1992-01-31
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Granted: 1993-05-11
•
Expires: 2012-01-31
Abstract
Abstract An electrically nonconductive composite article comprising a fibrillated polytetrafluoroethylene (PTFE) matrix, electrically conductive particles, and electrically nonconductive, energy expanded polymeric particles, which composite upon application of pressure thereto becomes electrically conductive and allows for the flow of electricity through the article. The articles are thin and can be used as a pressure sensitive pad or an interconnect for an electronic component.
Inventors
- 👤 Robin E. Wright
- 👤 William V. Balsimo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:35
CPC Classifications
C; C08; C08K; C08K7/00; C08K7/22; H; H01; H01B; H01B1/00; H01B1/20; H01B1/24; C08K9/00; C08K9/02; C08L; C08L27/00; C08L27/02; C08L27/12; C08L27/18; H01B1/22; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249986; Y10T428/26; Y10T428/268; Y10T428/31504; Y10T428/31551; Y10T428/31645; Y10T428/31649
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
27 words
An electrically nonconductive composite article comprising a polytetrafluoroethylene fibril matrix having enmeshed therein (a) electrically conductive metal-containing particles, and (b) electrically nonconductive, energy expanded hollow polymeric particles.
Claim 2
Dependent Claim
27 words
An electrically nonconductive composite article comprising a polytetrafluoroethylene fibril matrix having enmeshed therein (a) electrically conductive metal-containing particles, and (b) electrically nonconductive, energy expanded hollow polymeric particles.
Claim 3
Dependent Claim
25 words
The composite article according to claim 1 wherein the weight ratio of conductive particles to nonconductive particles is in the range of 999:1 to 3:1.
Claim 4
Dependent Claim
25 words
The composite article according to claim 1 wherein the weight ratio of total particles to fibril matrix is in the range of 98:2 to 75:25.
Claim 5
Dependent Claim
18 words
The composite article according to claim 1 wherein said conductive particles are metal particles or metal coated particles.
Claim 6
Dependent Claim
20 words
The composite article according to claim 4 wherein said metal or metal coated particles are powder, flakes, bubbles, or beads.
Claim 7
Dependent Claim
22 words
The composite article according to claim 1 wherein said conductive particles have a size in the range of 0.1 to 600 micrometers.
Claim 8
Dependent Claim
19 words
The composite article according to claim 1 wherein said conductive particles have a resistivity of less than 10 ohm-cm.
Claim 9
Dependent Claim
22 words
The composite article according to claim 1 wherein said nonconductive expanded particles have a polymeric shell and a liquid or gaseous core.
Claim 10
Dependent Claim
55 words
The composite article according to claim 8 wherein said nonconductive expanded particles have shells comprising copolymers selected from the group consisting of vinyl chloride and vinylidene chloride, vinyl chloride and acrylonitrile, vinylidene chloride and acrylonitrile, styrene and acrylonitrile, methyl methacrylate and styrene, methyl methacrylate and ethyl methacrylate, methacrylonitrile and acrylonitrile, and methyl methacrylate and orthochlorostyrene.
Claim 11
Dependent Claim
23 words
The composite article according to claim 1 wherein said expanded particles have a size in the range of 0.12 micrometer to 1000 micrometers.
Claim 12
Dependent Claim
18 words
The composite article according to claim 8 wherein said shell of said nonconductive expanded particles is poly(vinylidene chloride-co-acrylonitrile).
Claim 13
Dependent Claim
17 words
The composite article according to claim 8 wherein said shell of said nonconductive expanded particles is poly(methacrylonitrile-co-acrylonitrile).
Claim 14
Dependent Claim
23 words
The composite article according to claim 1 which is a membrane having a thickness in the range of 0.010 cm to 1.5 cm.
Claim 15
Dependent Claim
25 words
A pressure sensitive element comprising a polytetrafluoroethylene fibril matrix, having enmeshed therein a) electrically conductive particles, and b) electrically nonconductive, energy expanded hollow polymeric particles.
Claim 16
Dependent Claim
25 words
A pressure sensitive element comprising a polytetrafluoroethylene fibril matrix, having enmeshed therein a) electrically conductive particles, and b) electrically nonconductive, energy expanded hollow polymeric particles.
Claim 17
Dependent Claim
31 words
The element according to claim 14 wherein said electrically conductive particles are selected from the group consisting of carbon, metal, and particles coated with at least one of carbon and metal.
Claim 18
Independent Claim
77 words
A method comprising the steps of: a) providing an electrically nonconductive element comprising a polytetrafluoroethylene fibril matrix having enmeshed therein 1) electrically conductive particles, and 2) electrically nonconductive, energy expanded hollow polymeric particles, and b) applying external pressure to said element while said element is subject to an electrical potential so as to effect a decrease in electrical resistance of at least a portion of said electrically nonconductive element to allow for the flow of electrical current.
Claim 19
Independent Claim
77 words
A method comprising the steps of: a) providing an electrically nonconductive element comprising a polytetrafluoroethylene fibril matrix having enmeshed therein 1) electrically conductive particles, and 2) electrically nonconductive, energy expanded hollow polymeric particles, and b) applying external pressure to said element while said element is subject to an electrical potential so as to effect a decrease in electrical resistance of at least a portion of said electrically nonconductive element to allow for the flow of electrical current.
Claim 20
Dependent Claim
26 words
The method according to claim 16 wherein said electrically conductive particles are carbon or metal, or particles coated with at least one of carbon and metal.
Claim 21
Dependent Claim
15 words
The method according to claim 16 wherein said electrically conductive particles are silver coated particles.
Claim 22
Dependent Claim
13 words
The method according to claim 16 wherein said external pressure is fingertip pressure.
Claim 23
Dependent Claim
32 words
The method according to claim 16 further comprising the step of removing said external pressure so as to effect an increase in electrical resistance and cause the electrical current to cease flowing.
Claim 24
Dependent Claim
20 words
The method according to claim 16 wherein said external pressure is applied to said element at more than one location.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-05-10 | 1996-11-09 | 1997-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-10 | 2000-11-09 | 2001-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-10 | 2004-11-09 | 2005-05-11 | $7700.00 | Window Closed / Lapsed |